1. Field
Example embodiments relate to oscillators and method of operating the same.
2. Description of the Related Art
Oscillators generate signals in regular periods and are mainly used in wireless communication systems (e.g., mobile communication terminals, satellite and radar communication devices, wireless network devices and automobile communication devices) in addition to analog sound synthesizers.
Main factors of an oscillator may include a quality factor, output power and phase noise. Performance of the oscillator may improve greatly as a quality factor and output power increases, and phase noise decreases. As communication devices are required to have high performance and to be minimized, and as an operational frequency band increases, there is a demand for the development of a small oscillator having a high quality factor, low phase noise and high output power.
In this regard, spin torque oscillators using a spin transfer torque phenomenon have been introduced. The spin torque oscillators may be manufactured to be significantly smaller than general inductor and capacitor (LC) oscillators and film bulk acoustic resonator (FBAR) oscillators, and have relatively high quality factor. Thus, the spin torque oscillators have drawn attention as next generation oscillators.
However, general spin torque oscillators need a large magnetic field for high frequency oscillation. For example, in order to generate a frequency of about 10 GHz, a magnetic field of about 1000 oersted (Oe) (i.e., 0.1 tesla (T)) should be applied to general spin torque oscillators. However, it is actually difficult to supply such a large magnetic field.